The objective was to evaluate the effect of phytogenic supplementation in the feed of lactating sows on the performance parameters of sows and suckling piglets. Ninety-three lactating sows of commercial lines (sows TN70) were distributed in a completely randomized design. The treatments adopted were a control diet without phytogenics (control) and a control diet with phytogenic supplementation in the feed. Performance parameters and the behaviors of sows and piglets were evaluated, in addition to milk composition and the biochemical parameters of the animals. The use of phytogenics did not affect the feed intake or tissue mobilization of the sows. However, it improved the production and quality of milk and reduced the possibility of light piglets at weaning by 22.16 percentage points. Regarding biochemical parameters, phytogenics improved animal recovery in the lactation period, as proven by an increase in the serum concentration of total protein and urea. Sows that received phytogenics exhibited increased behaviors of inactivity (3.16%), breastfeeding (1.15%), and water consumption (0.95%). In conclusion, using phytogenics in the feed of lactating sows improves the performance of the litters without affecting the body condition of the sows, with increased milk production and enhanced protein and lactose concentration.